Quick Answer
An Ironman 70.3 covers 1.9 km swim + 90 km bike + 21.1 km run = 113 km total, with an 8 hr 30 min cut-off. A full Ironman 140.6 covers 3.8 km swim + 180.2 km bike + 42.2 km run = 226.3 km total, with a 17-hour cut-off. The 70.3 is exactly half the full Ironman distance.
Ironman Distances at a Glance
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| Distance | Swim | Bike | Run | Total (km) | Cut-off |
|---|---|---|---|---|---|
| Ironman 70.3 | 1.9 km | 90 km | 21.1 km | 113 km | 8 hr 30 min |
| Full Ironman 140.6 | 3.8 km | 180.2 km | 42.2 km | 226.3 km | 17 hours |
Ironman 70.3: The Half Distance
The Ironman 70.3 — named for its total distance in miles — is the most popular long-course triathlon format in the world. In metric terms it covers a 1.9 km open-water swim, a 90 km bike ride, and a 21.1 km run (a half marathon), totalling 113 km. Most age-group athletes finish between 5 and 7 hours, with the cut-off set at 8 hours 30 minutes at most events.
The 70.3 is significant because it’s challenging enough to require genuine preparation but realistic to fit around full-time work and family. Most athletes train 8–12 hours per week over a 12–20 week plan. The bike is the largest time segment and the leg that most influences your run — going too hard on the 90 km ride is the most common reason athletes struggle in the final half marathon. Our guide to training time for an Ironman 70.3 covers weekly structure in detail.
The 70.3 World Championship rotates annually to a new location and draws elite and age-group athletes from around the world. “Ironman 70.3” is a trademarked brand — independent races at the same distance are called “half iron-distance” or “middle-distance” races but cover identical distances.
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| Segment | Distance | Avg Time (Men 35–39) | Avg Time (Women 35–39) | Cut-off |
|---|---|---|---|---|
| Swim | 1.9 km | ~36 min | ~40 min | 1 hr 10 min |
| T1 | — | ~4 min | ~5 min | — |
| Bike | 90 km | ~2 hr 45 min | ~3 hr 10 min | — |
| T2 | — | ~3 min | ~3 min | — |
| Run | 21.1 km | ~2 hr 00 min | ~2 hr 20 min | — |
| Total | 113 km | ~5 hr 30 min | ~6 hr 20 min | 8 hr 30 min |
Full Ironman 140.6: The Original Distance
The full Ironman is the race that started the sport. It consists of a 3.8 km open-water swim, a 180.2 km bike ride, and a 42.2 km marathon run — completed consecutively in a single day within a 17-hour cut-off. The total distance is 226.3 km. The 140.6 figure is the imperial equivalent in miles.
The race originated in Hawaii in 1978, when Navy Commander John Collins combined three existing endurance events to settle a debate about which type of athlete was the fittest. The winner crossed the line in 11 hours 46 minutes. Today there are over 50 sanctioned Ironman events annually worldwide, with the Ironman World Championship held in Kailua-Kona, Hawaii.
The average finish time across all age groups is around 12–13 hours. The cut-off is 17 hours total, with intermediate cut-offs: the swim must be completed within 2 hours 20 minutes of the start, and the combined swim and bike within 10 hours 30 minutes. Full details on each cut-off and how they are enforced are in our guide to Ironman cut-off times.
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| Segment | Distance | Avg Time (Men 35–39) | Avg Time (Women 35–39) | Cut-off |
|---|---|---|---|---|
| Swim | 3.8 km | ~1 hr 10 min | ~1 hr 20 min | 2 hr 20 min from start |
| T1 | — | ~10 min | ~12 min | — |
| Bike | 180.2 km | ~6 hr 00 min | ~6 hr 45 min | Swim + bike within 10 hr 30 min |
| T2 | — | ~8 min | ~10 min | — |
| Run | 42.2 km | ~4 hr 50 min | ~5 hr 30 min | 17 hr total |
| Total | 226.3 km | ~12 hr 40 min | ~13 hr 35 min | 17 hours |
70.3 vs Full Ironman: How They Compare
The distances are exactly doubled from 70.3 to full Ironman, but the difficulty does not simply double. The full distance is disproportionately harder — particularly the marathon run after 180 km on the bike. At the 70.3 you run a half marathon on tired legs. At the full Ironman you run a complete marathon after spending the better part of a day swimming and riding. Fuelling, pacing, and mental resilience become far more critical at the longer distance.
Training volume increases significantly too. A 70.3 can be prepared for in 12–20 weeks at 8–12 hours per week. A full Ironman typically requires 20–30 weeks at 10–18 hours per week, with long bike rides of 5–7 hours and long runs approaching 30 km in the peak phase.
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| Ironman 70.3 | Full Ironman 140.6 | |
|---|---|---|
| Total distance | 113 km | 226.3 km |
| Cut-off time | 8 hr 30 min | 17 hours |
| Avg finish time | 5–6.5 hrs | 12–14 hrs |
| Training lead time | 12–20 weeks | 20–30 weeks |
| Weekly training hours | 8–12 hrs | 10–18 hrs |
| Longest training ride | ~4 hrs | 5–7 hrs |
| Longest training run | ~2 hrs | ~2.5–3 hrs |
| Race nutrition complexity | Moderate | High |
Ironman vs Iron-Distance: What's the Difference
“Ironman” is a trademarked brand owned by the World Triathlon Corporation (WTC). Only races they produce or licence can use the name. Races at the same distances run by independent organisations — Challenge Roth and the Challenge Family series being the most prominent — are called “iron-distance” or “full-distance” events. The distances are identical.
In the broader triathlon community, completing any race of the 226.3 km or 113 km distance earns you the relevant title regardless of brand. Challenge Roth in Germany is widely considered the fastest iron-distance course in the world, and the elite course records are held there. For most age-group athletes the brand matters less than the distance, the course profile, and the race experience on offer.
Should You Do a 70.3 Before a Full Ironman?
Yes — for the vast majority of athletes, completing at least one 70.3 before attempting the full distance is strongly recommended. The 70.3 teaches race-specific skills that are hard to replicate in training alone: open-water swimming in a mass start, transitions under race pressure, pacing the bike when adrenaline makes it tempting to go too hard, and managing nutrition across several hours of sustained effort.
Arriving at your first full Ironman having already raced a 70.3 means you know your swim pace in open water, have tested your nutrition strategy, and understand how your body responds to the bike-to-run transition. Most coaches recommend 1–2 70.3s as preparation before stepping up to 140.6, ideally completed in the same or prior racing season.
If you’re choosing your first full Ironman race, our guide to the most beginner-friendly Ironman courses highlights flat, fast events that suit first-timers well.
The Ironman World Championship and Qualification
The Ironman World Championship is held annually in Kailua-Kona, Hawaii — the pinnacle event in long-course triathlon. A second championship in Nice, France was introduced to expand access for European athletes, with the two venues alternating as the primary host. Professional athletes qualify through a points-based ranking system. Age-group athletes qualify by placing in the top positions of their age group at sanctioned qualifying events worldwide — competition for slots is fierce, and many athletes attempt multiple qualifiers over several years before earning a Kona spot.
A separate 70.3 World Championship is held annually at a rotating location, with its own qualification pathway through 70.3 qualifying events. Both championships are significant goals for competitive age-groupers and require a structured multi-year approach to reach.
Get the Right Training Plan for Your Ironman Distance
The jump in training commitment between the 70.3 and the full distance is significant. Having a structured plan that matches your goal time, current fitness, and weekly availability makes a material difference — not just in how the race goes, but in how sustainable the build feels across 5–7 months. For a full year-long approach, the 12-month Ironman training guide maps the full periodisation from base to race day. The 80/20 triathlon training method explains how most coaches distribute intensity across the week to build fitness without burning out. For a structured 24-week full Ironman build, the 24-week Ironman training plan guide covers the full phase-by-phase structure.
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FAQ: Ironman Distances Explained
How long is a full Ironman triathlon in km?
A full Ironman covers 226.3 km: a 3.8 km swim, 180.2 km bike, and 42.2 km run. It must be completed within a 17-hour cut-off.
What is the difference between Ironman 70.3 and a full Ironman?
A 70.3 covers exactly half the full distance — 1.9 km swim, 90 km bike, 21.1 km run (113 km total) with an 8 hr 30 min cut-off. A full Ironman doubles every leg to 3.8 km, 180.2 km, and 42.2 km (226.3 km total) with a 17-hour cut-off.
How long does the average person take to finish an Ironman 70.3?
Around 5–6 hours for most age-group athletes. Men aged 35–39 average around 5 hours 30 minutes; women in the same group around 6 hours 20 minutes. The cut-off is 8 hours 30 minutes.
How long does the average person take to finish a full Ironman?
Around 12–13 hours. Men aged 35–39 average around 12 hours 40 minutes; women around 13 hours 35 minutes. The cut-off is 17 hours.
Should I do a 70.3 before a full Ironman?
Yes. At least one 70.3 is strongly recommended first. The race-day experience — open-water swimming, transitions, pacing, and nutrition under race conditions — is difficult to replicate in training and makes a real difference when you step up to the full distance.
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